Sunday, 29 August 2021

What are the future research needs in flotation?

This will be the topic of debate at one of the two panel discussions at Flotation '21 in November.

Dynamic young researchers from around the world will share their views, and take questions from conference delegates, in the discussion chaired by Romke Kuyvenhoven, who joined Capstone's Minera Santo Domingo in Chile earlier this year, as Director Technical Services and in charge of the development of the mine plan and Cu/Fe/Co concentration/recovery. 

In 2014 Romke, then with Gecamin, was conference manager for the IMPC in Santiago Chile and is 1st left on the great photo below, at the Farewell function.

Romke, with Osvaldo Bascur, Pablo Brito-Parada, Barbara and Barry Wills,
Jan Cilliers, Robin Batterham, Guvan Onal and Kevin Galvin

Representing the UK on the panel is Dr. Pablo Brito-Parada (3rd left in the photo) of Imperial College, London. Pablo is an editor of Minerals Engineering and his work on froth flotation includes the modelling of complex phenomena in the pulp and froth zones and the use of experimental techniques to characterise these systems. He has led optimisation testwork at flotation plants worldwide to enhance metallurgical recovery and assess flotation cell design.

There is more published research on flotation from China than from any other country at present, and representing Central South University, Changsha, the number 1 ranked of the 38 universities in China with mineral processing departments, is Dr. Zhiyong Gao. He is also a Minerals Engineering editor and an outstanding researcher in one of the main thrusts of the mineral processing department at CSU, flotation chemistry. In 2018 Zhiyong was promoted to Vice-Dean of the School of Mineral Processing and Bioengineering at CSU making him the youngest Vice-Dean, at 34 years of age, among the 30 schools at CSU. He was a very worth recipient of the 2018 MEI Young Person's Award.

Presenting Zhiyong with his award at Flotation '19

The latest recipient of the MEI Young Person's Award is Dr. Ahmad Hassanzadeh, from Iran. He recently joined the impressive team at Maelgwyn Mineral Services, one of the Flotation '21 sponsors. He was awarded an Erasmus Exchange Program grant in 2016 and exchanged as a PhD candidate in the Department of Mineral Resources Engineering at the Montan University of Leoben, Austria. Later, in December 2018, he successfully defended his PhD thesis on the effect of hydrodynamic parameters on particle-bubble interactions in flotation and graduated from the Mineral Processing Department of Istanbul Technical University.  

During the last year of his doctorate program Ahmad was selected by Helmholtz-Zentrum Dresden-Rossendorf, Germany, as a post-doctoral research associate and worked two years (2018-2020) in the Processing Department of Helmholtz Institute Freiberg for Research and Technology (HIF), Germany.

The head of mineral processing at HIF is Dr. Martin Rudolph, who will represent Germany on the panel. Martin was highlighted as a Rising Star in 2018 and as a PhD student published and presented many papers receiving the first prize in the International Young Scientist Competition in St. Petersburg, Russia at the Gornyi Institute (Mining Institute) in April 2012, in the section on nanotechnologies. He has a special interest in nanoparticle systems and interfacial phenomena and colloidal interactions.

Martin (centre) at the Festo booth at Flotation '17

Representing Australia will be Dr. Liza Forbes, a Senior Research Fellow at the JKMRC. Liza's main interest lies in integrating fundamental and applied aspects of flotation research, to develop new and improved processing technologies. She specifically focuses on flotation reagent chemistry, mineral surface chemistry and base-metal sulphide electrochemistry. Liza graduated with a PhD in Chemical Engineering from the University of Cape Town in 2007. Since then, she has worked at the N.B.Keevil Mining Institute, University of British Columbia; the Department of Chemical and Biomolecular Engineering, University of Melbourne; and CSIRO Mineral Resources. Previously she worked at a metallurgist at the Bafokeng Rasimone Platinum Mine, Anglo Platinum in South Africa. She has since been involved with a number of industry research projects with companies such as Kennecott Copper Co, Zijin Mining, Newmont, Newcrest, Sytec Technology Solutions and Anglo Coal.

Liza (centre) with Amanda Wills and Nee San Yap at Flotation '17

Dr. Ronel Kappes will represent North America on the panel. She is Director of Processing at Newmont Goldcorp Corporation, USA. Ronel has metallurgical development experience in a wide-range of commodities,including gold, copper, lead, zinc and platinum group metals and is passionate about flotation, gold hydrometallurgy and mineral processing in general. Her background includes fifteen years as a metallurgical technical expert with Newmont Mining, with international experience through her time working on a variety of projects including operations and projects located in Ghana, Australia, Peru and Indonesia. She also serves as Newmont's Executive Sponsor and liaison with the University of Utah.

This is a panel discussion not to be missed if you have any interest in what the major areas of research should be focused on in the next few decades.

And a final reminder that if you would like to present your work at Flotation '21, the abstract deadline is the end of this week.


Thursday, 26 August 2021

The race to produce 'home-grown' lithium hots up

The latest report from the Intergovernmental Panel on Climate Change is bleak to say the least, and the science is strong enough now to leave little doubt that humans are playing a major role in climate change, even if natural forces are also at work.

Electric vehicles are part of the suite of solutions that could stave off the worst effects of global warming and air pollution. Lithium-ion batteries are the heart of EVs and as lithium is one of the most critical of metals the search is hotting up for 'home-grown' sources of lithium, and in particular innovations in processing brines and hard rock, reducing the reliance on China which processes much of the world's important battery metal. It is estimated that lithium demand could triple by 2025 to one million tonnes per year and then double again to two million tonnes per year by 2030 – the year the UK plans to ban new petrol and diesel car sales. Early in the month US President Joe Biden announced an executive order requiring 50% of all vehicles sold in USA to be electric by 2030! 

Batteries for an electric car are assembled at the Audi production plant in Brussels
Credit: Audi AG

With a typical lithium mine producing 30,000 tonnes per year the market needs approximately four new mines per year to keep pace with demand. However, experts point out that it takes five to seven years to discover, develop and put a lithium mine into production.

There has been much activity around the world in recent months, with news of new sources of the metal and innovations in processing, some of which are are highlighted here:

In general, lithium is produced either via hard rock mining, mainly for spodumene, or by extracting the mineral from South American brine deposits. Both methods have been criticised for their impacts on the environment.

There was news a few weeks ago that the USA's General Motors is investing in domestically sourced lithium. The company said that it is the first investor in an Australian company’s project to extract lithium from the Salton Sea Geothermal Field near Los Angeles, a huge area in the Imperial Valley that is already home to 11 geothermal power stations. The Controlled Thermal Resources “Hell’s Kitchen” lithium extraction project is expected to begin producing lithium in 2024. As with the Cornish Lithium project (see posting of 20th August for the latest news), it will be powered by renewable energy, using a closed-loop direct extraction process that returns spent brine to its underground source,

As with General Motors, the BMW Group will be accelerating its expansion of e-mobility in the coming years and will be sourcing lithium from a second leading supplier, US-based Livent.

The BMW Group had already signed a contract for the procurement of lithium from hard-rock deposits at Australian mines back in 2019 and is now broadening its supplier base and additionally sourcing lithium from Argentina, where the raw material is obtained from brine from salt lakes. Livent employs an innovative method, that emphasises sustainable water use and minimises the impact on local ecosystems and communities.

The world's second largest mining company, Rio Tinto, announced 4 weeks ago that it will spend $2.4 billion building a lithium mine in Serbia, from an entirely new mineral source, jadarite (LiNaSiB3O7OH). What makes the deposit unique is that both boron and lithium are contained in one mineral, which was new to science and which was later confirmed as a new mineral by the International Mineralogical Association. Rio Tinto’s Serbian team named it jadarite, 

Rio said its Jadar project in Serbia is expected to start operating in 2026 and hit full-production in 2029. The investment, which still depends on Rio Tinto being granted the necessary permits in the eastern European nation, would turn the company into a top-10 lithium producer globally and position it “as the largest source of lithium supply in Europe for at least the next 15 years.”

Rio Tinto is targeting an initial mine life of 2.3 million tonnes of lithium carbonate over 40 years. Following ramp-up to full production in 2029, the mine will produce roughly 58,000 tonnes of lithium carbonate, 160,000 tonnes of boric acid (borates are used in solar panels and wind turbines) and 255,000 tonnes of sodium sulphate.

There is also much fundamental research activity going on to extract lithium and other critical metals.

Researchers at King Abdullah University of Science and Technology have developed what they believe is an economically viable system to extract high-purity lithium from seawater, which contains 5,000 times more lithium than what can be found on land, but is present at extremely low concentrations of about 0.2 parts per million. The research team has tested a method that had never been used before to extract lithium ions. They employed an electrochemical cell containing a ceramic membrane made from lithium lanthanum titanium oxide. In a paper published in the journal Energy & Environmental Science, the researchers explain that the membrane’s crystal structure contains holes just wide enough to let lithium ions pass through while blocking larger metal ions.

Scientists at the University of Oxford are proposing the idea of sustainably extracting copper, gold, zinc, silver and lithium from brines trapped in porous rocks at depths of around 2 kilometres below dormant volcanoes. In a paper published in the journal Open Science, the researchers explain that the gases released by magma beneath volcanoes are rich in metals. As the pressure drops, the gases separate into steam and brine. Most metals dissolved in the original magmatic gas become concentrated in the dense brine, which in turn gets trapped in porous rock. The less-dense and metal-depleted steam continues up to the surface, where it can form fumaroles, such as those seen at many active volcanoes.

According to the research team this trapped subterranean brine is a potential ‘liquid ore’ containing a slew of valuable metals, including gold, lithium and several million tonnes of copper, all of which could be exploited by extracting the fluids to the surface via deep wells. Employing this method could potentially reduce the cost of mining and ore processing. In addition, since geothermal power would be a significant by-product of this green-mining approach, operations would be carbon-neutral.

There are risks to this proposal, though. The main ones are related to the technology that has to be used as the process involves drilling into rock at 2 kilometres depth and at temperatures of more than 450°C. On top of this, the extracted fluids are corrosive, which places limits on the types of drilling materials and they tend to dump their metal load in the well-bore, a problem known as ‘scaling.’ These limitations mean that more research needs to be done around the dynamics of fluid flow and pressure-temperature control in the well-bore and that there will be a need to develop resistive coatings to prevent well-bore corrosion.

And on a less positive note for lithium, it has been reported that an alliance between Graphene Manufacturing Group and The University of Queensland is developing more sustainable graphene aluminum-ion batteries with a life up to three times greater than lithium-ion and with the ability to charge 70 times faster. They are also said to have a very low fire potential and a lower environmental impact than their Li-ion counterparts because they are more recyclable.

And only 3 weeks ago the world's biggest battery supplier, Chinese company Contemporary Amperex Technology, a major supplier to Tesla, unveiled a sodium-ion battery, a type of lower-density cell that uses cheaper raw materials than batteries made from lithium-ion metals. As well as a first generation of sodium batteries the company also launched a battery-pack solution that can integrate sodium-ion cells and lithium-ion cells into one case, compensating for the energy-density shortage of the former while preserving its advantages.

A company spokesman said "sodium-ion batteries have unique advantages in low-temperature performance, fast charging and environmental adaptability and they are compatible and complementary with lithium-ion batteries. Diversified technical routes are an important guarantee for the long-term development of the industry".

Diversified technology is also being explored by Lithium Australia, who feel that there may be a better way than incorporating nickel and cobalt in lithium-ion batteries, which is expensive and possibly problematic in terms of safety, supply chain disruptions and provenance (of cobalt in particular). One of the company's subsidiaries has recently been granted an Australian patent for the production of battery active phosphate materials. The patent covers lithium ferro phosphate variants that improve performance through the addition of elements like manganese and vanadium, producing a new generation of battery materials.

It is evident that much is happening in the crucial development of future battery technology and that despite innovative new developments lithium will be in high demand for decades to come. Anticipating a world dominated by electric vehicles, materials scientists are working on two big challenges. One is how to cut down on lithium and other metals in batteries that are scarce, expensive, or problematic because their mining carries harsh environmental and social costs. Another is to improve battery recycling, so that the valuable metals in spent car batteries can be efficiently reused. 

Battery- and carmakers are already spending billions of dollars on reducing the costs of manufacturing and recycling electric-vehicle batteries. National research funders have also founded centres to study better ways to make and recycle batteries. Because it is still less expensive, in most instances, to mine metals than to recycle them, a key goal is to develop processes to recover valuable metals cheaply enough to compete with freshly mined ones. It is one of the great challenges in mineral processing and will be highlighted at MEI's Sustainable Minerals '22 next July.

And a final thought: when the Taliban seized control of the Afghan government on August 15th, they gained the ability to control access to huge deposits of lithium and rare earth minerals that are crucial to the global clean energy economy. In 2010, an internal US Department of Defense memo called Afghanistan “the Saudi Arabia of lithium,” after American geologists discovered the vast extent of the country’s mineral wealth, valued at at least $1 trillion. Ten years later, thanks to conflict, corruption, and bureaucratic dysfunction, those resources remain almost entirely untapped (more info at Quartz).

“The Taliban is now sitting on some of the most important strategic minerals in the world,” said Rod Schoonover, head of the ecological security program at the Council on Strategic Risks, a Washington think tank. “Whether they can or will utilise them will be an important question going forward.” 

"As long as there are safer and more reliable sources elsewhere, full utilization of Afghan minerals is likely to remain slow,” Schoonover said. However, China and Russia are already retaining diplomatic ties with the Taliban, and will almost certainly do business with the new regime on its home turf.


Monday, 23 August 2021

Glencore Technology's Jameson Concentrator Division is the latest sponsor of Flotation '21

Glencore Technology has been successfully marketing technology in the metals and mineral processing industries for almost 40 years. It has offices in Australia, South Africa, Canada, Chile, Russia, China and the UK, and is a wholly owned subsidiary of Glencore

Glencore Technology markets and supports the well known Jameson Cell, which has been successfully installed in 350 installations across 30 countries, and we are pleased to welcome the company back, via their Jameson Concentrator Division, as a sponsor of November's Flotation '21.

Jameson Cells

The Jameson Concentrator combines various configurations of Jameson Cell, modified and proven to process even larger volumes, and can add new generation small-footprint IsaMill™ technology where greater and precise liberation is needed. This state-of-the-art full circuit concentrator is based on industry learnings from over 133 IsaMill™ and 420 Jameson Cell installations across 30 years.

We celebrated the 30th birthday of the Jameson Cell at Flotation '19 with its inventor, Prof. Graeme Jameson, who will be very much involved with Flotation '21, as he has with all MEI's flotation conferences. 

Graeme Jameson and Glencore Technology's Virginia Lawson
cut the 30th Anniversary Jameson Cell cake
Prof. Jameson will be a panelist in the Future of Flotation Machines and Circuits panel discussion, chaired by Peter Amelunxen, Vice-President of Technical Services for Hudbay Minerals, Canada. Under Peter's guidance a Jameson Concentrator flotation plant consisting entirely of Jameson Cells has been built at Hudbay's New Britannia operation (posting of 7th April 2020), with Glencore Technology engaged for technical support. 

Flotation '21 is shaping up to be a great conference, and we thanks all our sponsors for their support- and a reminder that the end of the month deadline for abstracts is fast approaching.

Current sponsors

Updates are at #Flotation21

Friday, 20 August 2021

August Cornish Mining Sundowner: News of CSM, geothermal energy, lithium processing and women in mining

Cornwall is bursting at the seams with tourists at the moment and Falmouth's Gyllyngvase beach has been packed, so yesterday's Cornish Mining Sundowner was moved back a few metres into the adjacent Queen Mary Gardens. Due to early rain the turnout was, however, fairly low, with only 14 of the regulars appearing.

Most of those attending had some connection to Camborne School of Mines and there was talk of Exeter University’s decision to end recruitment to undergraduate mining engineering for the first time in the 134-year history of CSM (posting of 13 September 2020), which means that there will be no intake of undergraduate mining engineering students this year. Sadly, at a time when the importance of the mining industry is paramount, there is no longer an opportunity for international or home students to study BEng Mining Engineering in the UK.

The irony of this is that this year CSM undergraduate subjects have once again come top of the National Student Satisfaction survey within Exeter University and CSM’s Mining Engineering programme has earned Exeter University its first ever Global Top 10 ranking. The halt to recruitment was implemented shortly after the CSM Association had completed collaborative work on a 5-year strategy for CSM, at the centre of which was a new, purpose-built, dedicated training and education facility, to be known as the Centre of Mining Excellence.

This month the University will be assessing the level of practical support from industry for a flexible, ‘sandwich-style’ Bachelor of Engineering Programme in Mining Engineering. The programme is being designed by CSM mining staff who will continue to highlight the need to meet domestic and international industry requirements to deliver future mining engineers and mine managers.

Let's hope all this come to fruition, and it will be the first major challenge for Prof. Stephen Hesselbo, who has been appointed the new Head of CSM to follow Prof. Kip Jeffrey.  Stephen is an outstanding Earth Sciences researcher who joined CSM in 2013 from the University of Oxford. I was hoping that he might make his sundowner debut last night, but instead it was good to see a former Head of School, CSM's Prof. Frances Wall, with her daughter Alexandra Sweeney, project coordinator for Met4tech, who looks after social media for the Cornwall Mining Alliance, an industry associate for a number of MEI Conferences.

Alexandra and Frances

Frances is very much involved with research into critical minerals and agreed last night to present a keynote at next year's Sustainable Minerals '22. Earlier in the week we also had a similar agreement from Prof. Selo Ndlovu, of Wits University, only the second woman to have held the post of President of the Southern African Institute of Mining and Metallurgy,

The loss of the mining degree comes at a time when it has been great to see so many young women graduating in mining engineering, something which would have been unheard of when I was at CSM last century, as would a female head of CSM and a woman SAIMM President. In the July sundowner posting former CSM geology lecturer Richard Edwards commented on the visit of CSM MSc Mining Geology students to Ireland for a mix of activity which included a visit to Silvermines. When the group arrived he was told that the girls would not be allowed to go underground, as it would bring bad luck for the mine! "Good to see the times they are a-changing" said Richard. The sad irony of this is that 3500 miles away Afghanistan is returning to medieval rule with women and girls likely to suffer most. President Joe Biden, having withdrawn American troops, has effectively washed his hands of the country, while Boris Johnson says that the UK is looking at 'diplomatic solutions'.   

To rub salt in the wounds it was deeply disappointing to hear that Afghans who received Chevening Scholarships from the UK government to study in the UK this year were told that they would not be granted visas due to "administration issues." After intensive petitioning, and amid fears among the students that their scholarships could make them targets of the Taliban, Johnson intervened to say efforts would be made to accelerate their visas, hours after the Foreign Office defended its decision to prevent them taking up places this September. Let's hope that they, and their families, find a way to leave the country amidst all the chaos.

At a time when new blood is needed for the mining industry, developments in Cornwall proceed at a fast pace. Earlier in the month Geothermal Engineering Limited (GEL) announced that it was seeking development of a plant with two deep wells on land at Penhallow, near Perranporth. It hopes to go live in 2022 producing power and heat from the hot granite rocks, which will be used to supply a housing development for up to 10,000 people on the outskirts of Truro. The company has lodged a 'screening opinion' with Cornwall Council to see whether an Environmental Impact Assessment is required in preparation for a planning application for three more geothermal power plants at sites near Pool, Helston and Porthtowan.

It was great to see Dr. Tony Batchelor last night, the man who started all this, known affectionately as the 'father of Cornish geothermal energy'. While at CSM as a rock mechanics lecturer he initiated, and was the Project Director, of the UK/EEC Hot Dry Rocks geothermal project, and in 1985 he and others from the project formed GeoScience Limited, which he now owns. Until May of last year Geoscience was project manager and Delivery Partner for GEL's United Downs Deep Geothermal Power project.

Tony Batchelor (2nd left) with Pete Shepherd, Nick Clarke and Nigel MacDonald

As an added bonus GEL recently announced that concentrations of lithium higher than 250mg per litre had been found at depth, higher than in geothermal waters anywhere else in the world, the company now believing it could be able to produce 4,000 tonnes of lithium a year by 2026.  

At the July mining sundowner there was news that Cornish Lithium was testing different technologies to extract the metal from the hot geothermal brines a kilometre below the earth, and after removing the lithium injecting the water back underground so the process can be repeated. The energy used to power this process will be from a renewable source, the natural heat from the deep rocks being converted into electricity, making the process carbon-neutral.

During the G7 conference the project received a lot of media attention, due to the increasing global awareness of the responsible production of lithium. GeoCubed, a collaboration between Cornish Lithium and GEL has recently been established to construct a pilot plant to assess the potential for co-producing lithium and geothermal energy, and announced at the end of last month that French extraction tech firm GeoLith has been selected to provide their Direct Lithium Extraction (DLE) technology for the pilot plant, which is due to be commissioned at United Downs in West Cornwall by the end of March 2022 with a nominal capacity of 10 tonnes of Lithium Carbonate Equivalent per year.

GeoLith has developed a novel "Li-Capt" process that allows direct extraction of lithium from all waters and brines. It also offers the "Li-Mag" process, which allows the purification of concentrated lithium brines. The pilot plant aims to confirm that lithium can be produced in Cornwall from geothermal brine. It will process the 140 square metres of deep geothermal water successfully obtained during GEL's recent testing at its United Downs site.

"The Pilot Plant being constructed at Cornish Lithium's test site at United Downs will enable us to demonstrate what modern, low-carbon mineral extraction looks like as well as demonstrating the viability of DLE technology on Cornish geothermal waters," said Jeremy Wrathall, CEO and Founder of Cornish Lithium.

Hopefully there will be more good news at the next Cornish Mining Sundowner, scheduled for September 16th from 5.30pm, with a welcome return, after 19 months, to Falmouth's Chain Locker pub.


Tuesday, 17 August 2021

Prof. Raj K. Rajamani, 1948-2021

There was very sad news this week from USA of the sudden death last Friday of popular University of Utah Professor Raj Rajamani. He was well known for his work on comminution, particularly the discrete element simulation of ball mills and semi-autogenous mills, and for his contribution to computational fluid dynamics.  Most recently his successful research included contributions on high pressure grinding and electrodynamic sorting of light metals and alloys.

Prof. Rajamani at Comminution '10 in Cape Town

Raj graduated from the Dept. of Chemical Engineering at Annamalai University, Madras, India, in 1969. He obtained an M. Tech. in Chemical Engineering from the Indian Institute of Technology, Kanpur, in 1971, before moving to the University of Utah, where he completed his M.E. Chemical Engineering in 1973 and a Ph.D. in Metallurgy, in 1979. He then joined the staff of the Department of Metallurgical Engineering, becoming a full Professor in 1994.

In 2009 Raj was the recipient of the SME's Antoine M. Gaudin Award, “For his seminal work in the application of discrete element methods in the modeling of charge motion in semi-autogenous and ball mill grinding, and for his contribution to the basic science of comminution and classification”. Other awards include the SAG High Flyer Award in 2001 for outstanding contributions toward the development of autogenous and semi-autogenous grinding technology, and the Mellow Met Award for Excellence in Teaching in 1995, Department of Metallurgical Engineering, University of Utah.

Our thoughts at this time are with Raj's wife, Sudda, and their two daughters, and I invite all of you who knew Raj to leave your memories in the comments below.

Sunday, 15 August 2021

Developments in flotation circuit diagnostic practice

An important role of a site metallurgist is to diagnose reasons for problems in a flotation circuit and devise strategies to overcome these problems. Traditionally this has involved performing and analysing information from a flotation circuit survey. 

It is difficult to determine from this information alone definitive flotation mineral recovery mechanisms and strategies for circuit improvement. There are, however, new analytical and modelling techniques that can be used to complement traditional survey data. These techniques are able to determine the effect of mineralogy, surface chemistry and circuit design on flotation circuit recoveries and grades. They can suggest strategies for improvement which would not have been identified via a conventional circuit audit. 

In her keynote lecture at Flotation '21 Dr. Kym Runge will review these new approaches and use an industrial example to demonstrate the type of conclusions that can be derived. The developments that are required to improve analysis turnaround times and enable assessment of alternative flotation circuit options will be outlined.  

Associate Professor Kym Runge is the leader of the Separation Research Program at the SMI-JKMRC, Australia.  This program aims to develop novel separation processes that will make a step change in mining and involves research into high voltage comminution, coarse particle flotation, improved classification and novel flotation chemistries.  Prior to this appointment, Kym worked 25 years as a flotation specialist.  Her research has involved the development of flotation simulation and diagnostic procedures at the SMI-JKMRC, including the development of JKSimFloat, a flotation simulation program.  She also worked 10 years for Metso, the biggest mining equipment supplier, as a flotation consultant and researcher.

Updates on the conference are at #Flotation21 and the deadline for abstracts is the end of this month.

Thursday, 12 August 2021

"Diseases to which Miners of Metals are Exposed": the observations of Bernardino Ramazzini (1633-1714)

I am grateful to Dr. Franklin White for the following historical review of the early 18th century De Morbis Artificum: Diseases of Workers by Bernadino Ramazzini.

Franklin is the author of the recently published biography of his father, Frank White, Miner with a Heart of Gold (posting of 21st September, 2020) and of the historical reviews of De la Pirotechnia and De Re Metallica.

Introduction: Emerging Sciences of the Late Middle Ages

Expanding European economies during the fifteenth and sixteenth centuries spurred demand for gold and silver, as a basis for currencies as well as for jewelry.  As underground mining expanded to meet this demand, recognition and concern for the health and safety of miners and metal workers increased. 

The first publication dealing with the hazards of an occupation was a brochure written in 1472 by Ulrich Ellenbog, a physician of Augsburg, Germany.  His focus was preventive: to inform goldsmiths and others working with gold and silver how to avoid the toxic effects of such metals as mercury and lead.[1]

The first published account on the ill-health of miners and ways of preventing this was published by Agricola in 1556, in his famous treatise De Re Metallica.  However, this account was secondary to his detailed descriptions of mining and smelting.[2] 

Eleven years later, in 1567, the first monograph on the occupational diseases of miners and smelter workers, appeared in Germany. Its author was Theophrastus Bombastus von Hohenheim, also known as Paracelsus. Entitled Von der Bergsucht oder Bergkrankheiten (on Miners’ Sickness and other Diseases of Miners), he discussed etiology, pathogenesis, prevention, diagnosis and therapy.[1]

Agricola and Paracelsus were “renaissance men”: broadly educated in the arts, botany, mineralogy, mining, medicine, and natural philosophy.  Among other initiatives, they inspired a movement among physician-scholars focused on the health hazards and consequences of different fields of work.  

The first full scale treatise focused entirely on occupational health was De Morbis Artificum diatriba, a dissertation by Bernadino Ramazzini (1633-1714), a physician-scholar of Modena, Italy.[3] 

About Bernardino Ramazzini

Ramazzini was born in 1633 at Carpi, an ancient town dating from the Etruscan culture of north-central Italy. It was then known for its straw plaiting industry, and today remains an active industrial and crafts centre. Earning a medical doctorate at Parma in 1659, he continued his studies in Rome. He then practised as a public physician in the towns of Canino and Marta in Viterbo province. On moving to Modena in 1671, he was in favour with the ducal family of Este.[1] When the University of Modena was established in 1678, he was appointed Professor of the Theory of Medicine.[4] Addressing public health issues such as epidemic typhus, he can also be viewed as an epidemiologist. 

In 1700 he was appointed chair of Practical Medicine at the University of Padua, where he launched his De Morbis Artificum diatriba (published at Modena in the same year). Based not only on his clinical observations, it drew from his innumerable visits to worksites where he observed actual hazards associated with different occupations. From this he developed his core principle: 

“a prudent diagnostician will inquire first of all as to a new patient’s occupation, since the condition of the humours… is profoundly affected by the kind of work in which he is engaged.”[3]

He recognized that how people lived and worked directly influenced their health:

“Many an artisan has looked at his craft as a means to support life and raise a family, but all he has got from it is some deadly disease, with the result that he has departed this life cursing the craft to which he has applied himself”[3]

At that time, when the attention of doctors was devoted to the most wealthy patients, it was unexpected and unusual that a doctor devoted his attention to investigate workers’ health issues.[4]

“…many of our own clinicians would laugh at any… professor… if they saw him… descending to explore regions underground so as to investigate the hidden recesses of nature… But let them learn from… Galen (129 – c. 216) …who went down into… (a ferrous sulphate cave-mine)… to a depth of about one-eighth of a mile and observed… green water dripping into a pool… of a suffocating and almost intolerable odor…” workmen hastily carrying out this acidic water.[3]

He understood the connection between working conditions, health and public policy: 

“Not only in antiquity but in our own times also laws have been secure good conditions for workers; so it is right that the art of medicine should contribute its portion for the benefit and relief of those for whom the law has shown such foresight...”[3]

De Morbis Artificum diatriba 

Each chapter of the “diatriba” describes a disease(s) associated with a particular type of work followed by supporting literature where it existed, workplace descriptions, questions and advice for workers, and remedies. He recognized that not all workers' diseases were attributable to exposures to chemical or physical agents in the work environment: many appeared to be caused by motions and postures. 

In the first edition, Ramazzini discusses 42 groups of workers, the very first chapter – perhaps most notably - being devoted to miners. Of potential interest to modern miners are chapters on gilders, chemists, potters, tinsmiths, glass workers, sulphur workers, blacksmiths, gypsum and lime workers, stone cutters, and salt makers. A second edition, published in 1713, added 12 more groups, including coppersmiths, grinders, and brick makers.[3]  He died in the following year, at the venerable age of 81 years. 

"Diseases to which Miners of Metals are Exposed."

This chapter opens with the generic statement:

“Various and manifold is the harvest reaped by certain workers from the crafts and trades that they pursue; all the profit they get is fatal injury to their health… from two causes. The first and most potent is the harmful character of the materials that they handle, for these emit noxious vapours and very fine particles inimical to human beings and induce particular diseases; and second I ascribe to certain violent and irregular motions and unnatural postures of the body, by reason of which… serious diseases gradually develop therefrom.”[3]

He quotes the ancient Roman poet Ovid (43 BC – 17/18 AD):

“Men go down into the bowels of the earth, and what she has hidden away and consigned to the Stygian shades they dig out, wealth, provocative of evils.”[3]

He immediately acknowledges that Ovid was referring to moral evils, but then argues that the same statement may be applied to “the evils that attack men’s bodies”, listing examples such as the following (my medical translations in parentheses):[3] dyspnoea (shortness of breath), phthisis (tuberculosis), apoplexy (unconsciousness), paralysis (loss of motor function), cachexy (wasting), swollen feet (self-explanatory), joint pains, and palsy (loss of motor control e.g., tremors). He emphasizes:  “…the lungs and brain of … workers are badly affected, the lungs especially.”[3]

He considered mercury mining the most lethal, citing Gabriele Falloppio that “mercury miners can hold out for barely three years”, and Michael Ettmuller that within four months “they become subject to palsy of the limbs, paralytic, and suffer from vertigo” … caused by “the mercurial spirits which are… injurious to the nerves.”[3]   These descriptions remain consistent with 21st century medical science. 

He notes: 

“…mines are either damp because water keeps settling at the bottom of the shaft, or they are dry, and… fire sometimes has to be used… in splitting the rocks.  In damp mines that contain stagnant water the legs of the miners are affected, not only by the dense and poisonous vapours… but also… when the fragments of split rock fall… and… workers are suffocated and fall headlong… Moreover… when (fire)… is needed to soften rocks it elicits… pernicious fumes from the mineral substances, so that the… miners are plagued by every one of the elements.”[3]

He makes the following social commentary: 

“The mortality of those who dig minerals is very great, and women who marry men of this sort marry again and again.”[3]

Among his sources, he cites Agricola, Lucretius, Bernardo Cesi, Jesuit author of Mineralogia (1636), and Ramelow who wrote a German treatise on paralysis and palsy among metal workers, among others. He refers to works of art depicting slavery in ancient mining, pointing out that the conditions of his own day are not necessarily improved upon this. He advocates to church leaders.[3] 


Bernadino Ramazzini is considered the founder of the field of occupational medicine. His “diatriba” gave prominent attention to the diseases of metal miners, while addressing ultimately the health implications of some 54 occupations. He is aligned with the “scientific revolution”, a transformative period for ideas across mathematics, physics, astronomy, and biology based on verifiable evidence. Translated into French, German and English, Ramazzini’s book remained the major text for this branch of preventive medicine until the early 19th century when industrialization created new complexities requiring new approaches.


1. George Rosen.  Introduction to the Translation. Diseases of Workers by Bernardino Ramazzini. New York Academy of Medicine. The History of Medicine Series. No. 23 Hafner Publishing Company. New York, London 1964.
2. Franklin White. De Re Metallica: treatise of Georgius Agricola Revisited. Annals of the Royal College of Physicians and Surgeons of Canada. 1994;27:163-6.
3. Bernardino Ramazzini. Diseases of Workers. Translated from the Latin text. De Morbis Artificum of 1713 by Wilmer Cave Wright. 546 pages. Academy of Medicine. The History of Medicine Series. No. 23 Hafner Publishing Company. New York, London 1964.
4. Giuliano Franco. Editorial. A Tribute to Bernardino Ramazzini (1633-1714) on the tercentenary of his death. Occupational Medicine. 2014; 64(1):2-4. 

Monday, 9 August 2021

Future flotation circuits and machines

There have been major innovations in flotation machines over recent years, which has led to developments and improvements in flotation circuits.

So where is all this going, what will flotation circuits look like in future years, and what will be the major developments in flotation machine design?

This will be the subject of one of the panel discussions at Flotation '21 in November and we seek your views on this, which will be of help to the chairman of the conference, Peter Amelunxen, Vice-President of Technical Services for Flotation '21 sponsor Hudbay Minerals, Canada, and the first recipient of the MEI Young Person's Award back in 2011.

Peter Amelunxen with the 2018 Young Person's Award winner,
Dr, Zhiyong Gao, at Flotation '19

Under Peter's guidance a flotation plant consisting entirely of Jameson Cells has been built at Hudbay's New Britannia operation (posting of 7th April 2020), with Glencore Technology engaged for technical support. Flotation '19 gave the Hudbay team an opportunity to discuss results, share ideas, and build relationships with Glencore and with Prof. Graeme Jameson, the inventor of the eponymous cell.

We are privileged to have Prof. Jameson on the panel. A Laureate Professor at the University of Newcastle, Australia, he has been honoured as a Fellow of perhaps the most prestigious scientific organisation in the world, the Royal Society (posting of 15th May 2018) . He has presented research papers at all MEI’s Flotation conferences and was a keynote lecturer at Flotation ’09 with his paper New Directions in Flotation Machine Design. He is a long-standing member of the Editorial Board of Minerals Engineering and is the recipient of many major awards, including the Australian Prime Minister’s Prize for Science.  In 2013 he was awarded the SME’s prestigious Antoine Gaudin Award in Denver and I was pleased to nominate him for International Mining’s Hall of Fame, into which he was inaugurated in 2014. In 2016 he was the recipient of the IMPC's Lifetime Achievement Award. Prof. Jameson's life and work will be the subject of the first keynote lecture at the conference, given by Prof. Jim Finch, also a recipient of the  IMPC Lifetime Achievement Award and the Antoine Gaudin Award.

Profs. Jameson and Finch at Flotation '15

Professor Jameson has made an outstanding contribution to the Australian economy and the environment as the inventor of what is considered by many to be the nation's biggest export earner in the last 25 years. In the true mark of a scientist, 30 years on from his initial breakthrough discovery, and at the age of 85, he is still fine-tuning and improving the Jameson Cell, and pushing the boundaries of flotation with his new invention the coarse flotation NovaCell, which he feels is much more important, because if flotation can be achieved at coarser particle sizes less grinding is needed, using less energy and resulting in less wear and tear on the grinding equipment. 

There should be interesting discussion on coarse flotation between Prof Jameson and fellow panelist Dr. Eric Wasmund, the Vice President of Global Flotation Business with Flotation '21 sponsor Eriez Flotation Division, Canada. Eriez invented and market the Hydrofloat Cell, for flotation at coarse particle sizes, and the Eriez Flotation product line encompasses flotation cells, gas spargers, mini-pilot plants, slurry distributors and flotation test equipment. The company has designed, supplied and commissioned more than 900 column flotation systems worldwide for cleaning, roughing and scavenging applications in metallic and non-metallic processing operations.  It is also well known for its StackCell®, a small stackable mechanical cell offering reduced mixing in the cell and shorter residence times, which was featured, along with the Hydrofloat Cell, at Flotation '19

Eric Wasmund (2nd left) at the Eriez booth at Flotation '19

Dr. Dariusz Lelinski, the Global Product Director of sponsor FLSmidth, USA, has been a regular contributor to the flotation series. A respected mineral processing expert with international experience in product and process design, test planning, results evaluation, survey and industrial operation support, he will lead the FLSmidth team which will launch the WEMCO nextGEN flotation machine at the conference.

Dariusz Lelinski (2nd left) at Flotation '19. Also in the picture are Martin Rudolph (left)
and Romke Kuyvenhoven (2nd right) who will be involved
with the first panel discussion at Flotation '21

Prof. Juan Yianatos, of Santa Maria University, Chile, is the 4th member of the panel. Juan was President of the XXVII IMPC, which was held in Santiago, Chile in 2014. A long serving member of the Minerals Engineering Editorial Board, he will bring to the panel his expertise in applied research on process modelling, diagnosis and control, particularly in flotation including column flotation.

Juan Yianatos with Prof. John Monhemius
at the IMPC in Quebec, 2016

We look forward to a dynamic panel discussion, and a reminder that if you would like to make a presentation at the conference, abstracts should be submitted by the end of this month.  Updates can be found at #Flotation21.

Thursday, 5 August 2021

Major green company Metso Outotec to sponsor Sustainable Minerals '22

Sustainability is a top priority for Metso-Outotec, so it is great to be able to announce that they will be sponsoring Sustainable Minerals '22 next year, joining ZEISS Microscopy as early sponsors.

The year 2020 was transformational for Metso Outotec, who started as two companies and by the 1st of July had formed the new company, whose vision is to be the customers’ number one choice for sustainable use of earth’s natural resources. The company has set Science Based Targets (SBT) in alignment with limiting global warming to 1.5°C. They aim to reduce CO2 emissions by 50% in their own production by 2030, 20% in logistics by 2025 and 20% in product use phase by 2025. They are also targeting that 30% of the supplier spend by the end of 2025 is with partners who have set a SBT emission target. 

In January Metso Outotec was ranked 8th on the Corporate Knights 2021 Global 100 Index of most sustainable companies in the world, and placed as a top-ranking company among its peers. We are more than proud to have Metso Outotec involved with Sustainable Minerals '22.  Thanks also to our media partner, International Mining, and industry associates CEEC, Critical Minerals Association and Cornwall Mining Alliance.

There is now a first call for abstracts for the online conference, and updates will be posted at #SustainableMinerals22.

Sunday, 1 August 2021

July update: no end in sight for the pandemic

The pandemic still rages on, fueled in England by mass gatherings, such as the G7 summit in Cornwall in June (posting of 1st July) and July's major sporting events in London. The 2-week Wimbledon tennis tournament was watched by thousands, while at Wembley Stadium the semi-finals and final of Euro 2020 were attended by tens of thousands of football fans. There were egregious scenes inside and outside the stadium during the day of the final, where thousands of ticketless louts broke down barriers and entered the stadium, swelling the anticipated 60,00 attendance who watched England, in their first major final since the World Cup in 1966, lose on a penalty shoot-out to Italy. Days after the match it was reported that swathes of England fans had tested positive for Coronavirus

The final was part of a Government trial to test the safety of large events, allowing 60,000 fans to attend with no social distancing or masks after producing a negative test result. However, this did not allow for the thousands more who congregated outside and the dozens of ticketless fans who stormed the stadium.

Fans leaving Wembley stadium during Euro 2020

Despite Covid infections having risen to their highest level since early February, one of the highest in the world, hospitalisations and deaths are low, thanks to the NHS and the impressive vaccine roll-out, over 65% of adults in UK being fully vaccinated by the middle of the month. PM Boris Johnson therefore declared a very contentious 'freedom day' on July 19th, where virtually all Coronavirus restrictions were lifted, and we mere mortals were advised to behave sensibly and to make our own decisions on wearing masks, social distancing etc.

Crowds behaving sensibly during Euro 2020

Ironically two days before 'freedom day' the new Health Secretary Sajid Javid tested positive for Coronavirus, and Johnson and chancellor Rishi Sunak were both contacted by the NHS Track and Trace but decided not to self-isolate as it was said that they were taking part in a pilot programme where daily tests replace self-isolation, once more strengthening the feeling that there is one rule for the elite... Three hours later, amidst a tide of criticism, they decided that self-isolation was indeed the right thing to do!

Johnson's lifting of restrictions has been widely condemned worldwide, health experts calling it "a threat to the world", some experts worrying that the UK could become a breeding ground for variants. Even England’s chief medical officer, Prof. Chris Whity, conceded that the number of people in hospital with Covid in the UK was doubling about every three weeks and "could soon reach quite scary numbers”. He said “I don’t think we should underestimate the fact that we could get into trouble again surprisingly fast.” Having said that, there was a puzzling and rapid decline in infections on the last week of the month, giving rise to cautious optimism that the third wave of Covid might have turned the corner in the UK. The next few weeks will tell.

No matter what happens, the world is still a long way off opening to international travel and even some easing of restrictions hasn't reduced the nightmare of border control where people have been queuing for hours to show they are Covid-negative.

Although there have been a number of hybrid conferences- a mixture of online and face-to-face activities- none have been truly international, and it is likely to be a very long time yet before this happens. All MEI Conferences this year have been online, as will November's Flotation '21, originally scheduled for Cape Town. Comminution '22, also scheduled for Cape Town, has been postponed for a year, and Physical Separation '22, IntegratedMinPro '22 and Sustainable Minerals '22 are all online. Who know what will happen after that?